A born again Christian can have curses until they actively break it. When Jesus became a curse for us, it was a legal transaction that took place but we have to enforce it by 1) confessing the sins, iniquities and trespasses of our ancestors (& ours) and any other thing the Holy Spirit shows us to confess 2) break the curses associated with these sins, iniquities and trespasses off of us and future generations 4) cast out of our lives and future generations any demons attached to those curses. After we’ve done all this, then we have appropriated Galations 3:13; because a curse is not broken until it’s broken.
Just like we had to confess with our mouth and believe in our hearts that God raised Christ from the dead in order to be saved, so we have to believe in our heart that Jesus became a curse for us and break the curse outloud with our mouth. As stated above, in order to break the curse we first have to confess our ancestors sins and iniquities that brought curses into our lives.
In Ezekiel 18 God is declaring His desire that each person pay for their own sin and not the children pay for their father’s sins, but in order to for this to come to pass he commanded Israel to repent of their iniquties, otherwise it will be their ruin. In other words if they don’t repent of their iniquity it will pass on to their children and be their ruin as a people. So are many people groups and families who have the same sins, addictions, diseases, unfortune etc. run frpm generation to generation because it’s iniquitous, it’s curses. There will be no curse only in the Millenial Reign of Christ, until then we Christians actively have to break curses off of our lives in order to live out Galations 3:13.